Solvent refining with nitroalcohols



Patented Nov. 1, 1938 PATENT OFFICE SOLVENT aarmma wrrn NITBOALCOHOLS Glen H. Morey, Terre Haute, Ind., minor to Commercial Solvents Corporation, Terre Haute,

Ind., a corporation of Mary No Drawin wherein a, y, and 2 represent zero or integers. Specific examples of nitroalcohols included in my invention are 3-nitro-4-heptanol, 5-nitro-4-octanol, 2-methyl-2-nitro l-butanol, and 3-methyl-3-nitro-2-pentansol. These compounds may be prepared by any of the known general methods, but are most satisfactorily prepared as described in patent applications U. S. Ser. No. 146, 852, filed June '7, 1937, by H. B. Hass and B. M. Vanderbilt and U. S. Ser. No. 146,855, filed June 26 '7, 1937, by B. M. Vanderbilt which comprises reacting one mole of an aliphatic aldehyde with one mole of a primary nitro-parafiln. The invention contemplates extracting oil with any one of these compounds or their isomers, or with mixtures of 30 any two or more of them or their isomers.

Lubricating oils, such as those produced from Mid-Continent crude, are ordinarily composed of relatively paraflinic constituents, and also relatively non-paraiiinic constituents, including naphthenic, aromatic, and unsaturated hydrocarbons. A solvent of my invention is adapted to extract these relatively non-,parafiinic bodies from oil for the production of lubricating oil fractions which are of relatively high parafiinic character, and therefore have relatively lower viscosity gravity constants than the untreated oil (Ferris, Birkhimer, and Henderson, Ind. and Eng. Chem., 23, pp. 753-761 (1931)).

In the application of my invention to the treatment of mineral oils, I prefer to use the general method indicated in the following: One part of the oil is mixed with from one to four parts of solvent liquid, and this mixture is then heated while agitating to a temperature somewhat above 60 the critical solution temperature of the mixture in order to effect complete solution of the oil in the solvent. The mixture is then allowed to cool while slowly agitating to a temperature below that of the 'criticalsolution temperature; The

. agitation is discontinued and the two layers are land Application June "I, 1937, Serial No. 146,857

allowed to settle out. The temperatures employed will depend upon the particular nitroalcohol used, the nature of the oil undergoing treatment, the degree of separation desired, and also to some extent upon whether the solvent is used alone or in combination with a modifying solvent or diluent as hereinafter mentioned.

Upon settling, the mixture separates into two layers, the bulk of the solvent liquid containing the constituents which it is desired to extract from the oil, and the oil layer containing the undissolved and relatively parafiinic oil in admixture with a relatively small amount of solvent. The two layers are then separately withdrawn and the solvent liquid recovered therefrom. If desired, the separated layers may be subjected to treatment with additional quantities of the solvent for the purpose of obtaining a series of fractions of diflering characteristics. The solvent may be recovered from the oil by any suitable method such asfdistillation. Final traces .of the solvent may be removed from the oil by finally subjecting the mixture to the action of steam for a period of time at a temperature above the boiling point of the nitroalcohol employed.

I do not wish to be in any manner limited to the above described process for effecting the extractions. The extraction may be carried out in a continuous or semi-continuous system. The process may also be carried 'out at a constant temperature which is somewhat lower than the critical solution temperature of the oil and the nitroalcohol employed.

The following examples are presented in order to illustrate my invention. The oil used in these examples was a Mid-Continent crude having the following properties:

Specific gravity at C 0.9020 Saybolt viscosity at F sec 307.5 Saybolt viscosity at 210 F sec 51 Viscosity gravity constant at 100 FL. 0.846 .840

Viscosity gravity constant at 210 F Example I 1 separation was made at 112 C., however.

the liquid reached the temperature of 230 C., air being passed through at all times in order to re move completely'the solvent. The oil from the solvent layer had a viscosity gravity constant equal to .870 at.100 F., and .868 at 210 F. The purified oil layer had a viscosity gravity constant equal to .830 at 100 F., and .824 at 210 F.

Example II Two volumes of 5-nitro-4-octanol were mixed with one volume of oil and treated as in the previous example. The critical solution temperature of this mixture being about 51 C., the mixture was heated above this temperature and then cooled to about 31 C. at whichtemperature the liquid was separated and treated as before. The resulting oils had the following viscosity gravity constants:

Oil from Oil layer Solvent layer it#33 i:::::::::::::::::;::::::::::: 2%

Example In Two volumes of 2-methyl-2-nitro-l-butanol were mixed with one volume of oil and treated as above. In this case 'the critical solution temperature was about 152 C. and the separation was made at about 131 C. The resulting oils had the following viscosity gravity constants:

Oil from Oil layer Bolventlnyer h'zample-IV The same procedure was followed as in Example musing 2-methyl-2-nitro-1-butanol. s'lshe of the oil was recovered in the rafilnate which had a vistosity gravity constant of .833 at 100 F. and .828 at 210 F.

Example V Y Two, volumes of 3-methyl-3-nitroe2-pentanol were mixed with one volume of oil and treated as above. In this case the critical solution temperature was about 111 C. and the separation was made at about 81 C. 74% of the oil was recovered in the oil layer which had a viscosity gravity constant of .828 at 100 1". and .822 at F. 1 It will, of course, be readily recognizedthat certain of the nitroalcohols of this group will.

be more satisfactory than others for the extraction. For example, 2-nitro-1-butanol and 2-ni- 2,iss,4es

modifying solvent liquid, such as benzol or alight petroleum naphtha, or a petroleum fraction composed of propane, butane, or other similar low boiling hydrocarbons, for the purpose of facilitat-' ing the extraction and further controlling the. extent thereof. I

The lubricating oil distillate may be subjected to the foregoing extraction treatment either before or after dewaxing, or subsequent to treatment with other solvents or chemicals.

J The invention is not necessarily limited to the treatment of lubricating oil fractions, since the solvent may be adapted to the refining and. puriflcation of various hydrocarbon or mineral oil fractions, including naphtha, cracked naphtha, kerosene, etc., as well as residual or distillate fractions, or products derived from petroleum or other sources.

- Obviously many modifications and variations of the inventlonas hereinab'ove set forth may be madev without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims;

I claim-'1 1. The method of refininghydrocarbon oil containing relatively parafiinic vand relatively nonparaifinic constituents, including 'naphthenic, aromatic, and'unsaturated hydrocarbons, to remove the undesired relatively non-paramnic constituents therefrom, which comprises extractively l treating the oil with an aliphatic nitroalcohol whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid. 2. The method of refining hydrocarbon oil containing relatively paraillnic and relatively nonparaifinic constituents, including naphthenic, aromatic, and unsaturated hydrocarbons, to remove the undesired relatively non-paraflinic constituents therefrom, which comprises extractively treating the oil. with a nitroalcohol having the followinggeneral chemical formula:,

OaHl-nparafilnic constituents, including naphthenic,

aromatic, and unsaturated hydrocarbons, to remove the undesired relatively non-parafllnic constituents therefrom, which comprises extractively treating the oil with an aliphatic nitroalcohol containing less than 11 carbon atomsin the molecule, whereby the undesired constituents are separated from the oil as an extract soluble in the solvent 4. The method of refining hydrocarbon oil containing relati vely paraillnic and relatively nonparaillnlc constituents, including naphthenic, aromatic, and unsaturated hydrocarbons, to remove the undesired relatively non-paraflinic constituents therefrom, which comprises'extractively treating the oil with a nitroalcohol havingthe following general chemical formula:

NO; on-

,Ham wherein :r, 1 and 2. represent zero or integers and z+1l+z is less than nine, whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

5. The method of refining hydrocarbon oil containing relatively-parafllnic and relatively nonparaflinic constituents, including naphthenic, aromatic, and unsaturated hydrocarbons, to remove the undesired relatively non-para'flinic constituents therefrom, which comprises extractively treating the oil with 2-methyl-2-nitr'o-l-butanol, whereby the undesired constituents. are separated from the oil as an 20 liquid.

extract soluble in the solvent treating the oil with 3-nitro-4-heptanol, whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

GLEN H. MOREY. 20 

